Exam 1 Flashcards
Which of the following are true about behavior?
A. Behavioral choices exhibited by an animal are always adaptive
B. An ultimate explanation invokes evolutionary or historical mechanisms
C. Behavioral traits evolve to benefit a species
D. Most behaviors are determined by a single gene
B
Behavioral traits are typically _______
Polygenic
Genes involved in regulating behavior are typically ____
Pleiotropic
What are Tinbergen’s 4 Questions?
- What is the immediate causation of behavior
- How does the behavior develop?
- What is the evolutionary history of the behavior?
- What is the adaptive function of the behavior?
Example of Proximate approach
Analyze levels of stress hormones in the blood after the animal flees from an aversive stimulus
Example of ultimate approach
Study survival and genetic relatedness analyses to determine the evolutionary history of the behavior
Origin of Natural Selection
Darwin
Proximate and ultimate causes are _____
Complementary
Natural Selection is _____
A mechanism by which evolution could occur
Requirements of Natural Selection
- Variability
- Heritability
- More offspring produced than can survive
- Some variations are more successful
- Most favorable variations more likely to survive & reproduce
- Naturally selected individuals contribute more offspring to later generations
Natural selection is a ______
Passive filtering mechanism
Selection acts on heritable _____ variation in traits
Individual (not group)
_____ acting on differences among ____ within a population will usually have a stronger evolutionary effect than _____ acting on differences among _____
Darwinian selection
Individuals
Group selection
Groups
Evidence suggesting evolution
Geology (gradualism)
Homology
Paleontology
Example of Instinctive Behavior
A lizard flees from the sidewalk when a human approaches
Ethology
Focus on behavior under natural conditions
Views behavior as an evolutionarily adaptive trait
Behavioral ecology
Evolutionary basis for animal behavior due to ecological pressures
Adaptive significance
Beneficial qualities (increased survival and reproduction) a trait conveys
Genetic Differences
Can lead to behavioral differences that in turn drive differences in reproductive success
Scientific Approach
- Observations
- Form questions
- Hypotheses
- Testable Predictions
- Gather Data
- Refine, Alter, Expand or Reject Hypotheses
- Develop general theories
Variation + Heritability + Differential reproduction
Evolutionary Change
Genes
Segments of DNA encoding information for synthesis of proteins
Alleles
Different forms of a gene
Adaptation
Characteristic that confers higher inclusive fitness to individuals than any other existing alternative exhibited by other individuals within the population
Instinct
Hereditary inborn knkwledge
Methods to understand how genes influence behavior
- Crossbreeding experiments
- Artificial selection
- Hold environment constant (common garden, cross fostering)
Common garden experiment
If differences persist in 2 pop. w/ different behavior, then differences have genetic basis
The common garden experiment _____
Removes major environmental effects on behavior
Cross fostering
Parenting behavior is learned & inherited (Montane & Prairie voles)
The control of complex behaviors are typically ____
Polygenic
Behavior genes are often _____
Pleiotropic
Innate releasing mechanism
Neural network that processes a sign stimulus and then coordinates a fixed action pattern
How nervous system modulates behavior
- neuron firing rate increases with strength of stimulus
- number of neurons firing increases with strength of stimulus
- some nerve impulses require neurotransmitter
Learning
- Change in behavior based on experience
- Ability to learn is costly
- Allows plasticity and flexibility
Duetting in tropical wrens
Juveniles acquire duetting rules during early development
____ change the probability of a particular behavior
Hormones
A special case of learning is a ______ in response to a _____ stimulus
Fixed Action Pattern
Sign
Ex: Gull chicks
Feature detection
Nervous system sorts key info from background noise
Ex: Toad vision ignores perpendicular movement
Audiogram
Perpendicular axis: threshold in dB SPL
Horizontal axis: Frequency in kHz
Peaks mean different functions
Doppler effect in bats
Compensation by adjusting call frequency
(Lowers as it gets closer to prey
Frequency sensitivity
Bats discern small frequency differences within acute range of hearing
Place Theory
Ability to sense frequency depends on different sound frequencies selectively vibrating different areas of the cochlea
Stimulus filtering
Capacity to focus on relevant stimuli and filter out background of less relevant stimulus
What constraints do bats face in terms of using echolocation
Spreading losses, doppler shift, call masking returning echo
What do bats need to be successful at echolocation
Acute hearing & sensitivity in processing sound information
What adaptations have bat species developed to echolocate prey
Doppler shift compensation, auditory fovea, sensitivity in auditory cortex, specialized neurons to detect echoes
Hormones have major critical functions in ___
Reproduction & Survival
Organizational effects
Early development
Specific critical period
Irreversible
Activational effects
Adulthood
Reversible
Only when hormone is present
Why did young and colleagues perform gonadectomies on experimental groups?
Eliminate natural production of hormones by animals to experimentally control hormone exposure
Hormones mediate how behaviors change in response to _____
External stimuli
Why are spotted antbirds aggressive year round, although they have low sex steroid levels during non-breeding season?
Increased sensitivity to sex-steroids by non-reproductive brain
Androgens during gestation mediate ___
Aggression
Ex: genital masculinization in spotted hyena
Cognitive ethology
Clark’s nutcracker located caches by remembering where they put them
Canid generalization
All canids are good at interpreting social cues
Dogs vs. Wolves
Is imprinting proximate or ultimate?
Proximate because it has to do with development
True or False: Instinctual learning can be altered through development
False
Compare/Contrast instinct, imprinted, and learned behavior
Learned behavior develops over time with experience while instincts are innate and cannot be altered through development. Imprinting is a type of learned behavior that happens in a critical period. Imprinting and learned behavior are both proximate as they involve development of the animal.
